The present invention relates to a leadframe, a method of fabricating a light emitting diode package using the leadframe, and the light emitting diode package fabricated by the method, and more particularly to a leadframe having a heat sink support ring capable of fixing a heat sink to a leadframe to prevent the heat sink from being separated from a package body, a method of fabricating a light emitting diode package using the leadframe, and the light emitting diode package fabricated by the method.
The luminous power of the light emitting diode (hereinafter referred to as LED) is substantially proportional to the input power. Therefore, high luminous power can be obtained by increasing the electric power input to the LED. However, the increase of the input power results in the increase of the junction temperature of the LED. The increase of the junction temperature of the LED causes the loss of photometric efficiency which represents the conversion rate of input energy into visible light. Therefore, it is required to prevent the junction temperature of the LED from rising due to the increased input power.
One example of an LED package employing a heat sink to prevent the increase of the junction temperature of an LED is disclosed in U.S. Pat. No. 6,274,924 entitled “surface mountable LED package.” According to the U.S. Pat. No. 6,274,924, the thermal coupling of the heat sink to a LED die enables the LED die to maintain a low junction temperature. Therefore, relatively higher input power can be supplied to the LED die to obtain higher luminous power.
However, the prior LED package is not structurally stable, since the heat sink can be easily separated from the package body. When the heat sink is separated from the package body, bonding wires electrically connecting the leads and the LED die mounted on an upper portion of the heat sink are cut off to bring an irreparable damage to the LED package. Consequently, the LED package capable of preventing the separation of the heat sink from the package body is required.